I got this with my Ardweeny: avrdude: stk500_getsync(): not in sync: resp=0x00 avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51
It would happen with both Mac and PC (w/System 7 Home Premium).
It was fixed by removing the Ardweeny from the breadboard :)
This kit involves soldering pin strips to the ATmega328 pins. I guess the stretch from the breadboard broke some connections. I'm not sure what else it could be as the breadboard had no other connections.
Also, I had to install the FTDI drivers on System 7. This seems to only be required by some System 7 users. In programing environment, no serial ports were listed. Under Device Manager, Ports (COM & LPT), it should list USB Serial Port (COM3 or some other port). Right clicking on USB Serial Port should say it is working properly. If it shows up under another heading and right-clicking says no driver installed, then driver installation is required.